The present invention relates to smoking articles such as cigarettes, and in particular, to cigarettes having filter elements containing a carbonaceous material.
Popular smoking articles, such as cigarettes, have a substantially cylindrical rod shaped structure and include a charge of smokable material such as shredded tobacco (e.g., in cut filler form) surrounded by a paper wrapper thereby forming a so-called "tobacco rod." Normally, a cigarette has a cylindrical filter element aligned in an end-to-end relationship with the tobacco rod. Typically, a filter element includes cellulose acetate tow circumscribed by plug wrap, and is attached to the tobacco rod using a circumscribing tipping material. It also has become desirable to perforate the tipping material and plug wrap, in order to provide dilution of drawn mainstream smoke with ambient air.
Cigarettes are employed by the smoker by lighting one end thereof and burning the tobacco rod. The smoker then receives mainstream smoke into his/her mouth by drawing on the opposite end (e.g., the filter end) of the cigarette.
Certain cigarettes have filter elements which incorporate materials such as carbon. Exemplary cigarettes and filters therefore are described in U.S. Pat. Nos. 2,881,770 to Tovey; 3,353,543 to Sproull et al.; 3,101,723 to Seligman et al.; and 4,481,958 to Ranier et al. and European Patent Application No. 532,329. Certain commercially available filters have particles or granules of carbon (e.g., an activated carbon material or an activated charcoal material) dispersed within cellulose acetate tow; other commercially available filters have carbon threads dispersed therein; while still other commercially available filters have so-called "cavity filter" or "triple filter" designs. Exemplary commercially available filters are available as SCS IV Dual Solid Charcoal Filter from American Filtrona Corp.; Triple Solid Charcoal Filter from FIL International, Ltd.; Triple Cavity Filter from Baumgartner; and ACT from FIL International, Ltd. See, also, Clarke et al., World Tobacco, p. 55 (Nov., 1992).
Cigarette filter elements which incorporate carbon have the ability to change the character of mainstream smoke which passes therethrough. For example, such filter elements have the propensity to reduce the levels of certain gas phase components present in the mainstream smoke, resulting in a change in the organoleptic properties of that smoke.
However, such filter elements often incorporate relatively high levels of carbon (e.g., in particulate form), and/or are longitudinally segmented in format and configuration. As such, filter elements incorporating carbon require numerous and labor intensive processing steps; and cigarettes incorporating such filter elements often can be characterized as having slightly metallic drying and powdery flavor characteristics.
It would be desirable to provide a cigarette having a cigarette element incorporating carbon or other material capable of absorbing and/or adsorbing gas phase components present in mainstream cigarette smoke, which filter element can be manufactured in an efficient and effective manner.